The invention relates to a long-range optical device, in particular a sighting telescope, comprising an outer housing in which a reversal system is disposed between the objective lens and eyepiece, and having an adjusting mechanism for adjusting the sighting line by adjusting at least one optical component inside the outer housing and a resetting mechanism acting on the optical component which comprises at least one spring for generating the restoring force.
In long-range optical devices, in particular sighting telescopes of the type used for firearms for example, the sighted target is imaged in the objective lens plane laterally reversed and upturned. A reversal system disposed between the objective lens and eyepiece rights the image and reproduces it in the eyepiece plane, where it is viewed. The reversal system usually comprises at least two optical elements, e.g. what are known as cemented lenses, which are disposed at a distance from one another. The optical elements of the reversal system are grouped in an inner housing, also referred to as a mount or auxiliary tube. The reversal system therefore constitutes a component unit which is mounted inside the long-range optical device so that it can be adjusted.
In the case of long-range optical devices such as sighting telescopes, especially those used on weapons, a reticle (crosshairs, bar pattern or similar) is provided as an aid to sighting the target. The reticle is disposed either in the objective-end (first) or ocular-end (second) image plane or may also be reflected into the optical path.
In the case of sighting telescopes, a known approach is to provide adjusting mechanisms, known as “turrets”, which enable the sighting line in the sighting telescope to be adjusted in the vertical and/or in the horizontal direction. It is usually either the reticle or target mark that is adjusted or the objective lens. Accordingly, the sighting telescope, which is “test fired” for specific ammunition and a specific range for example, can be readjusted so that accurate shots can be fired at a target even at a different range and/or with different ammunition. Furthermore, other interference variables can also be compensated, for example an already existing setting angle of the sighting telescope if the target object is disposed at a different height from the marksman, as well as other environmental influences such as wind direction and strength.
To enable windage and elevation corrections to be made to the sighting telescope or to adjust the sighting line, the reversal system or the inner housing in which the reversal system sits must also be mounted so that it can also be adjusted in the telescope tube transversely to the optical axis. The reversal system may therefore be mounted (e.g. by means of a ball joint and (cone) socket) inside the telescope tube so that it is able to tilt. A ball seating for the reversal system is known from EP0654650B2, for example. Based on the prior art, an adjustment is made transversely to the optical axis, in other words the reversal system is tilted, by means of so-called elevation screws, which are usually disposed at a right angle and can be operated by means of adjusting turrets accessible from outside.
Various resetting mechanisms are known from the prior art as a means of resetting the reversal system.
For example, a known approach is to fit helical springs axially in the ball and socket joint. This being the case, however, there is a risk that the ball and socket joint might lift. Furthermore, the spring force varies considerably depending on the position of the reversal system.
Another system uses leaf springs disposed along or transversely in the main tube, which push directly onto the reversal system. If fitted transversely to the main tube, additional space can be made available for the spring by providing a recess in the main tube.
It is difficult to obtain a large adjustment path because of the material properties. Fitting is difficult and the spring force varies considerably depending on the position of the reversal system.
Another known option for a resetting mechanism is a helical spring which is fitted in the main tube radially at an angle of 45° and pushed directly onto the reversal system. A construction of this type is known from U.S. Pat. No. 2,189,766A, for example. The problem in this instance is that space has to be provided for retaining and guiding the spring and the housing therefore has to be made wider. Here too, the spring force is very much dependent on the position of the reversal mechanism. When the adjusting turrets are extracted and the spring is therefore relaxed, there is hardly any spring force available.
Another possibility of adjusting the direction of the sighting line is to leave the reversal system fixed inside the housing and instead mount the objective lens inside the housing so that it is able to pivot or tilt. Such an option is disclosed in EP 0 709 705 B1 or TW 2008 19711 A, for example.